The present invention relates generally to exterior panels for installation on high-rise buildings and, more particularly, to a uniquely configured beam assembly that is specifically adapted to hoist a plurality of panels into position on a building structure while maintaining a level or horizontal orientation of the beam assembly during sequential offloading of each panel.
Many modern building structures such as high rise office buildings are fabricated with a plurality of exterior panels which are fastened to the building structure during the final stages of construction. Such exterior panels may include window panels and/or other types of glazing and architectural panels which, when installation is complete, form an enclosure of the building. The size of the panels can be very large and, in some cases, can span several floors of the building. Due to the large size, such panels are relatively heavy and are therefore difficult to handle and maneuver, especially during windy conditions. In addition, the trend toward increasingly larger-sized exterior panels has necessitated the use of hoisting systems such as cranes having ever-increased lifting capacity in order to hoist the panels up the side of the building structure and maneuver the panel into position at the desired elevation.
As may be appreciated, some of the larger or taller buildings may require the installation of thousands of exterior panels. In conventional construction practices, each of these panels must be hoisted one-at-a-time up from the ground floor to many hundreds of feet into the air to the desired elevation where the panel is to be installed. Once hoisted to the desired elevation, the exterior panels must be maneuvered and positioned into place such that mounting brackets on each panel can be connected or attached to mechanical anchors that are affixed to the concrete slabs which form the floor of each story of the building.
As a result of the great heights or elevations to which each panel must be hoisted and maneuvered into position, the time required to complete the installation of all the exterior panels of a high-rise office building can be excessive. Factoring in labor costs such as the cost of renting a suitable lifting mechanism such as a tower crane, the installation of exterior panels on a high-rise office building can be prohibitively expensive and time consuming.
Included in the prior art are several attempts at reducing the overall costs of installing exterior panels on high-rise office buildings. For example, a document entitled “Beeche Exterior Cladding Installation System for High-Rise Buildings” and published in “Construction Innovation Forum” (2001) discloses a system wherein curtain wall panels are hoisted up to a desired position or elevation on the building structure using a crane such as a roof crane. The panels are hoisted up to a monorail system mounted on the building at elevation in a bottom-to-top installation sequence. The monorail allows the panels to be moved laterally into their final installation position on the building. The monorail system is secured to an exterior of the building perimeter. The curtain wall panels are suspended from a trolley suspender which allows for vertical final adjustment and positioning of the exterior panels for attachment to the building structure.
Although the exterior cladding installation system disclosed in the Beeche reference represents an improvement in reducing the overall time required to install exterior panels on a building structure, the same system presents certain drawbacks and deficiencies which detract from its overall utility. For example, the Beeche cladding installation system requires a variety of specialty fixtures and equipment which must be custom designed and manufactured in order to fit the specific size and configuration of the building structure to which it is to be mounted. For example, the Beeche system discloses the use of a space frame that must be erected and positioned at ground level adjacent the building structure so that panel sets may be offloaded from vehicle delivery systems such as a flat bed trailer.
The panels are suspended under the space frame while awaiting hoisting up to the desired elevation. The need for such specialized equipment such as the space frame reduces the overall cost-effectiveness of the Beeche installation system. Furthermore, the space frame occupies an area adjacent the building structure which presents an impediment to normal construction operations. Even further, the space frame presents a potential safety hazard to construction workers due to the large and heavy panels sets which are suspended at a height above the ground that allows workers to pass underneath.
A further disadvantage or drawback associated with the Beeche system is related to the specialty monorail which must be specifically designed, fabricated and installed on the building structure so that the panel sets may be suspended at the desired elevation once they are hoisted. As was mentioned above, the monorail system allows the panels to be moved laterally into their final installation position on the building. Furthermore, during the bottom-to-top installation sequence of the exterior panels, the monorail must be periodically disassembled and/or removed from the building structure for reassembly at the next higher elevation position so that the next set of exterior panels may be installed.
As can be seen, there exists a need in the art for a hoist system that is adapted for installing a plurality of exterior panels onto a building structure in a reduced amount of time and with reduced cost. Furthermore, there exists a need in the art for a hoist system for installing a plurality of panels onto a building structure which does not occupy work space around the exterior of the building at the ground floor. In addition, there exists a need in the art for a hoist system for installing a plurality of panels onto a building structure which reduces the risk of harm associated with relatively large exterior panels suspended near ground level. Finally, there exists a need in the art for a hoist system for installing a plurality of panels onto a building structure which is of simple construction, which is simple to use and which prevents scheduling conflicts with the many other types of construction activities that are typically associated with building construction.